Display device

ABSTRACT

According to one embodiment, a lateral-electric-field liquid crystal display device includes a light-emitting display layer including OLEDs and a driving circuit controlling light emission of the OLEDs, a moisture impermeable film provided to be laminated on the light-emitting display layer to prevent infiltration of moisture into the light-emitting display layer, an optical substrate provided separately from the moisture impermeable film and subjecting light from the light-emitting display region to optical processing, a first touch electrode group serving as one electrode group of touch electrodes and provided on a back surface of the optical substrate, and an extraction electrode group formed to be laminated on the moisture impermeable film, the extraction electrode group and the optical substrate have an overlapping part in plan view, and electrodes of the first touch electrode group being electrically connected to electrodes of the extraction electrode group in the overlapping part.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.15/889,915, filed Feb. 6, 2018, which is a continuation of U.S.application Ser. No. 15/379,309, filed Dec. 14, 2016, which is acontinuation of U.S. application Ser. No. 15/180,704, filed Jun. 13,2016, which is a continuation of U.S. application Ser. No. 14/995,972,filed on Jan. 14, 2016, which is a continuation of U.S. application Ser.No. 14/505,880 filed Oct. 3, 2014, now U.S. Pat. No. 9,262,030 and isbased upon and claims the benefit of priority from Japanese PatentApplication No. 2013-209238, filed Oct. 4, 2013, the entire contents ofall of which are incorporated herein by reference.

FIELD

Embodiments described herein relate generally to a display device.

BACKGROUND

Electronic apparatuses such as mobile phones, personal digitalassistants, and personal computers have been developed. Such electronicapparatuses are equipped with a display device including a touch panelfunction as a form of user interface. These electronic apparatusesusually include a capacitive touch panel function. In a capacitive touchpanel, conductive electrodes are disposed on the panel, and a contactposition of a finger or a pen on the surface of the panel is sensedbased on change in capacity between the electrode and the finger or thelike.

An electronic apparatus having the above touch panel function is knownas having a structure in which a touch panel board is separately bondedto a display device such as a liquid crystal display device and anorganic EL display device, to add a touch panel function.

In the meantime, in electronic apparatuses using a liquid crystal device(LCD), an in-cell structure is being generalized. In the in-cellstructure, a touch panel function is formed inside the LCD device.Adopting the in-cell structure produces the merit that the thickness andthe weight of the devices are reduced, because it becomes unnecessary touse a dedicated touch panel.

On the other hand, in OLED display devices using organic light emittingdiodes (OLED), it is difficult to provide a touch panel function insidein the same form as LCD devices, because a cathode provided on the wholelight-emitting display surface thereof serves as an electromagneticshield.

BRIEF DESCRIPTION OF THE DRAWING

A general architecture that implements the various features of theembodiments will now be described with reference to the drawings. Thedrawings and the associated descriptions are provided to illustrate theembodiments and not to limit the scope of the invention.

FIG. 1 is a cross-sectional view illustrating a structure of a displaydevice discussed prior to the invention.

FIG. 2 is a schematic diagram illustrating a structure of a touch panel.

FIG. 3 is a cross-sectional view illustrating a structure of a displaydevice according to a first embodiment.

FIG. 4A is a diagram for explaining a method for forming a moistureimpermeable film in the display device according to the firstembodiment.

FIG. 4B is a diagram for explaining a method for forming a moistureimpermeable film in the display device according to the firstembodiment.

FIG. 5A is a diagram for explaining a method for forming an extractionterminal in the display device according to the first embodiment.

FIG. 5B is a diagram for explaining a method for forming an extractionterminal in the display device according to the first embodiment.

FIG. 6 is a diagram illustrating arrangement of connection pads in thedisplay device according to the first embodiment.

FIG. 7A is a diagram illustrating a method for peeling the moistureimpermeable film and a method for exposing and extracting a drivingterminal in the display device according to the first embodiment.

FIG. 7B is a diagram illustrating a method for peeling the moistureimpermeable film and a method for exposing and extracting a drivingterminal in the display device according to the first embodiment.

FIG. 8 is a diagram for explaining a method for connecting the displaydevice according to the first embodiment to an external driving circuit.

FIG. 9 is a diagram illustrating a structure of touch electrodes in adisplay device according to a second embodiment.

FIG. 10 is a diagram illustrating a structure of touch electrodes in adisplay device according to a variation of the second embodiment.

FIG. 11 is a cross-sectional view illustrating a structure of a displaydevice discussed to be compared with the display device of the presentembodiment.

FIG. 12 is a cross-sectional view illustrating a structure of a displaydevice discussed to be compared with the display device of the presentembodiment.

FIG. 13 is a cross-sectional view illustrating a structure of a displaydevice discussed to be compared with the display device of the presentembodiment.

DETAILED DESCRIPTION

Various embodiments will be described hereinafter with reference to theaccompanying drawings.

In general, according to one embodiment, a display device includes alight-emitting display layer including a light-emitting display regionformed of OLEDs and a driving circuit controlling light emission of theOLEDs, a moisture impermeable film provided to be laminated on thelight-emitting display layer to prevent infiltration of moisture intothe light-emitting display layer, an optical substrate providedseparately from the moisture impermeable film and subjecting light fromthe light-emitting display region to optical processing, a first touchelectrode group serving as one electrode group of touch electrodes andprovided on a back surface of the optical substrate, and an extractionelectrode group formed to be laminated on the moisture impermeable film,the extraction electrode group and the optical substrate have anoverlapping part in plan view, and electrodes of the first touchelectrode group being electrically connected to electrodes of theextraction electrode group in the overlapping part.

First Embodiment

FIG. 1 is a cross-sectional view illustrating a structure of a displaydevice discussed prior to the present invention.

The display device illustrated in FIG. 1 comprises an OLED displaydevice 1, an adhesive layer 2, and a touch panel 3. Specifically, thetouch panel 3 is bonded onto the OLED display device 1 via the adhesivelayer 2.

The touch panel 3 includes first touch electrodes 3 a and second touchelectrodes 3 b that are placed on a touch panel substrate 3 c. The touchpanel substrate 3 c is formed of transparent glass or plastic. The firsttouch electrodes 3 a and the second touch electrodes 3 b are transparentelectrodes using a material such as ITO (Indium Tin Oxide) and a silvernanowire, and are arranged on the touch panel substrate 3 c as, forexample, a number of mosaic electrode patterns formed of columns androws. Each of the first touch electrodes 3 a and the second touchelectrodes 3 b is electrically connected to a touch signal controllingcircuit 11 via an FPC (Flexible Print Circuit) serving as a touchconnection component. The touch panel 3 senses an approaching (contact)position of a dielectric such as a finger by change in capacitance ofthe touch electrodes 3 a and 3 b.

The OLED display device 1 includes an array substrate 4, an OLEDlight-emitting display layer 5, a moisture impermeable film (sealinglayer) 6, a seal material 7, a filler 8, and an optical substrate 9 thatare provided on the array substrate 4.

The array substrate 4 is an insulating substrate formed of glass,quartz, ceramics, or plastic. The OLED light-emitting display layer 5 isprovided with a light-emitting layer including organic light-emittingdiodes (OLED), and a driving circuit to control light-emittingoperations of the OLEDs. The light-emitting layer is a thin filmincluding luminescent organic compound that emits light of red, green,blue, or an achromatic color. A TFT (thin-film transistor) that formsthe driving circuit is formed of low-temperature polysilicon. Thedriving circuit is supplied with a driving signal from a display panelcontrolling circuit 10 that is electrically connected via an FPC.

The colors of light emitted from the OLEDs are not necessarily dividedinto red, green, blue, and an achromatic color, but may be only anachromatic color. In such a case, the OLEDs may be used in combinationwith red, green, and blue color filters to emit light of red, green,blue, or an achromatic color.

The moisture impermeable film 6 seals the OLEDs and the thin-filmtransistor to prevent moisture from infiltrating from the outside. Theseal material 7 serving as a holding member is provided between themoisture impermeable film 6 and the optical substrate 9. The sealmaterial 7 is provided in a frame shape in peripheral regions of themoisture impermeable film 6 and the optical substrate 9, and a spacesurrounded by the moisture impermeable film 6, the optical substrate 9,and the seal material 7 is filled with the filler 8. The filler 8 is,for example, a thermosetting resin that prevents moisture frominfiltrating from the outside and enhances impact resistance.

The optical substrate 9 is properly provided with a member that subjectslight from the OLEDs to optical processing, such as an optical elementsuch as a color filter and a polarizer, and a black matrix. Although acolor filter is required in the case where the OLEDs emit light of anachromatic color as described above, a color filter is not alwaysrequired in the case where the OLEDs emit light of red, green, or bluecolor. A polarizer is provided in the case of reducing reflected light.

FIG. 2 is a schematic diagram illustrating a structure of the touchpanel 3.

The touch panel 3 is provided with a plurality of transparent firsttouch electrodes 3 a (line 1, line 2, . . . ) extending in thehorizontal direction and a plurality of transparent second touchelectrodes 3 b (line A, line B, . . . ) extending in the verticaldirection in a lattice shape. The first touch electrodes 3 a and thesecond touch electrodes 3 b are arranged in different layers via atransparent insulating film (not illustrated).

FIG. 2 illustrates the state where the finger touches a point close toan intersection point between the first touch electrode 3 a in line 2and the second touch electrode 3 b in line A. In this state, the fingerserving as a dielectric changes the mutual capacitance between the firsttouch electrode 3 a in line 2 and the second touch electrode 3 b in lineA. Thus, the position where the finger is located can be sensed bymeasuring the mutual capacitance between the first touch electrode 3 aand the second touch electrode 3 b.

The finger serving as a dielectric changes the self capacitance of thefirst touch electrode 3 a of line 2 or the self capacitance of thesecond touch electrode 3 b of line A. The term “self capacitance”indicates capacitance that exists between each first touch electrode 3 aor second touch electrode 3 b and the ambient conductor. Thus, it ispossible to sense the position where the finger is located, by measuringchange in self capacitance with the first touch electrode 3 a or thesecond touch electrode 3 b caused by touch of the finger.

For example, the sensing operation is executed as follows.

The touch signal controlling circuit 11 supplies a signal to the firsttouch electrode 3 a of line 1 and reads signals of the respective secondtouch electrodes 3 b (line A, line B, . . . ). Each of the read signalsincludes information relating to the mutual capacitance between thefirst touch electrode 3 a and the second touch electrode 3 b. Next, thetouch signal controlling circuit 11 supplies a signal to the first touchelectrode 3 a of line 2 and reads signals of the respective second touchelectrodes 3 b (line A, line B, . . . ). This operation is performedwith the first touch electrode 3 a successively switched, and therebythe position where the finger is present (the position of the firsttouch electrode 3 a and the position of the second touch electrode 3 b)can be sensed. The operation can be achieved by outputting, by the touchsignal controlling circuit 11, an alternative-current waveform signal(such as a square wave signal), switching the first touch electrode 3 ato be supplied with a signal in synchronization with thealternative-current waveform signal, and reading signals of therespective second touch electrodes 3 b (line A, line B, . . . ).

In the process of manufacturing the display device illustrated in FIG.1, first, the moisture impermeable film 6, the filler 8, and the opticalsubstrate 9 are laminated on the array substrate 4 provided with theOLED light-emitting display layer 5, to form the OLED display device 1.In addition, the touch panel 3 in which the touch electrodes 3 a and 3 bare provided on the touch panel substrate 3 c is formed separately.Then, at the final step of the display device, the touch panel 3 isbonded via the adhesive layer 2.

As described above, the display device having the structure illustratedin FIG. 1 requires a step of adding the touch panel 3 separately fromthe process of manufacturing the OLED display device 1. This structurecomplicates the process, and increases the cost. In addition, thisstructure has demerits such as increase in size in the thicknessdirection of the display device.

FIG. 3 is a cross-sectional view illustrating a structure of a displaydevice 100 according to the first embodiment. Constituent elementshaving the same functions as those of the display device of FIG. 1 aredenoted by same reference numerals, and detailed explanation thereof areomitted.

The display device 100 illustrated in FIG. 3 has a structure in which amoisture impermeable film 6, a seal material 7, a filler 8, and anoptical substrate 9 are laminated on an array substrate 4 provided withan OLED light-emitting display layer 5. In addition, a back surface (asurface opposed to the array substrate) of the optical substrate 9 isprovided with first touch electrodes 3 a, and a front surface of theoptical substrate 9 is provided with second touch electrodes 3 b.

The second touch electrodes 3 b are electrically connected to a touchsignal controlling circuit 11 via an FPC at an end part of the opticalsubstrate 9. On the other hand, an end part of the first touchelectrodes 3 a is not provided with an FPC to electrically connect tothe touch signal controlling circuit 11.

In the first embodiment, part of the region of the moisture impermeablefilm 6 is extended toward the side on which a signal line is drawn out,in comparison with the structure illustrated in FIG. 1. Then, anexternal extraction electrode 20 is formed on an upper layer of theextended region, and an end of the external extraction electrode 20 iselectrically connected to the touch signal controlling circuit 11 via anFPC. The other end of the external extraction electrode 20 is heldbetween the seal material 7 and the moisture impermeable film 6.

The seal material 7 includes conductive particulates such as Au-platedpearl material. Thus, by pressing the optical substrate 9 and themoisture impermeable film 6, electrodes at an end part of the firsttouch electrodes 3 a are electrically connected with electrodes at anend part of the external extraction electrode 20 via the conductiveparticulates. A connecting part 21 illustrated in FIG. 3 indicates theelectrically connected region. The connecting part 21 is an electriccircuit that is formed by pressing the optical substrate 9 and themoisture impermeable film 6.

Next, the process of manufacturing the display device 100 according tothe first embodiment will be explained hereinafter.

Formation of Moisture Impermeable Film

FIG. 4A and FIG. 4B are diagrams for explaining a method for forming themoisture impermeable film in the display device according to the firstembodiment.

As illustrated in FIG. 4A, the OLED light-emitting display layer 5including OLED light-emitting devices, a driving circuit, and a displaydriving external terminal 23 is formed on the array substrate 4. Theformation is performed with a step similar to that of a conventionalmethod. Then, as illustrated in FIG. 4B, the moisture impermeable film 6that covers the OLED light-emitting display layer 5 is formed on thewhole surface of the array substrate 4.

Formation of Extraction Terminal

FIG. 5A and FIG. 5B are diagrams for explaining a method for forming anextraction terminal in the display device according to the firstembodiment.

As illustrated in FIG. 5A, a pattern of the external extraction terminal20 is formed using a dry process such as mask deposition. A dry processis used to prevent deterioration of the OLED light-emitting devices dueto moisture. As illustrated in FIG. 6, a plurality of connection pads 24are arranged on the external extraction electrode 20. In FIG. 5A, forexample, a plurality of connection pads 24 are provided in a rangeindicated by a region 25.

FIG. 6 is a diagram illustrating arrangement of connection pads in thedisplay device according to the first embodiment.

As illustrated in FIG. 6, n extraction lines included in the externalextraction electrode 20 are extended into the region 25, and connectedwith n connection pads (24-1, 24-2, . . . , 24-n) provided at positionscorresponding to end parts of the n first touch electrodes 3 a. Theconnection pads 24 are electrically connected with the first touchelectrodes 3 a via the connecting part 21. FIG. 6 only illustrates anexample, and arrangement positions of the connection pads 24 in the sealmaterial can be properly determined in consideration of the structure ofthe first touch electrodes 3 a and the size of the frame region.

Then, in FIG. 5B, resin serving as a material of the seal material 7 isdisposed in a frame shape. As described above, the seal material 7includes conductive particulates such as Au-plated pearl material. Next,the filler 8 is filled into a space enclosed by the seal material 7.Thereafter, the optical substrate 9 on which the first touch electrodes3 a are formed is positioned such that the first touch electrodes 3 aare opposed to the array substrate 4, and the optical substrate 9 isbonded to the array substrate 4. In the bonding, the optical substrate 9and the array substrate 4 are pressed to hold the seal material and thefiller 8 therebetween, to form the connecting part 21.

Peeling the Moisture Impermeable Film and Exposing Driving Terminal

FIG. 7A and FIG. 7B are diagrams for explaining a method for peeling themoisture impermeable film and a method for exposing and extracting adriving terminal in the display device according to the firstembodiment.

First, as illustrated in FIG. 7A, the whole panel manufactured is putinto a sealing-layer-peeling gas to peel the moisture impermeable film6. This treatment removes the moisture impermeable film 6 in a regionother than the region covered with the optical substrate 9 and theexternal extraction electrode 20 in the plan view. As a result, theexternal extraction electrode 20 is formed at a position that is higherthan the array substrate 4 by the thickness of the moisture impermeablefilm 6. However, the difference in height between the moistureimpermeable film 6 and the array substrate 4 is minute.

Then, as illustrated in FIG. 7B, patterns of the second touch electrodes3 b and the external extraction electrode 26 are formed on the frontsurface of the optical substrate 9 by a dry process such as maskdeposition.

Connection to External Driving Circuit

FIG. 8 is a diagram for explaining a method for connection to theexternal driving circuit in the display device according to the firstembodiment. The upper part of FIG. 8 is a plan view of the displaydevice, and the lower part of FIG. 8 is a cross-sectional view of thedisplay device.

An FPC to connect to the display panel controlling circuit 10 isattached to the display driving external circuit 23 connected to theOLED light-emitting display layer 5. In addition, an FPC connected tothe touch signal controlling circuit 11 is attached to the externalextraction electrode 20 that is electrically connected to the firsttouch electrode 3 a, and another FPC connected to the touch signalcontrolling circuit 11 is attached to the external extraction electrode26 connected to the second touch electrode 3 b.

Both the two FPCs connected to the touch signal controlling circuit 11are attached in the same direction from the front surface of the displaydevice 100 toward the back surface of the display device 100. Inaddition, the FPC connected to the display panel controlling circuit 10is also attached in the same direction. Thus, the display device 100according to the present embodiment has an advantage of easierattachment of FPCs. Besides, because the difference in height betweenthe surface of the moisture impermeable film 6 and the surface of thearray substrate 4 is minute as described above, FPCs can be attached tothe display panel controlling circuit 10 and the touch signalcontrolling circuit 11 simultaneously.

In the first embodiment, a signal is supplied to the first touchelectrode 3 a provided on the back surface of the optical substrate 9 toread signals of the respective second touch electrodes 3 b. Inconsideration of attenuation of the signal in the connecting part 21, asense signal with a good S/N ratio is obtained by the above structure.However, the display device may have a structure in which a signal issupplied to the second touch electrode 3 b provided on the front surfaceof the optical substrate 9 to read signals of the respective first touchelectrodes 3 a.

With the display device according to the first embodiment explainedabove, it is possible to reduce the thickness and the weight of thedisplay device.

Second Embodiment

The second embodiment is different from the first embodiment in that ablack matrix BM of an optical substrate 9 also serves as first touchelectrodes 3 a. Constituent elements having functions that are the sameas or similar to those of the first embodiment are denoted by samereference numerals, and detailed explanation thereof are omitted.

FIG. 9 is a diagram illustrating a structure of touch electrodes in adisplay device according to the second embodiment. The lower part ofFIG. 9 shows a cross-sectional view of the display device according tothe second embodiment. Because the cross-sectional view is the same asthe cross-sectional view of the display device shown in the lower partof FIG. 8, detailed explanation thereof is omitted. The upper left partof FIG. 9 shows a plan view of the back surface of the optical substrate9 as viewed from inside. The upper right part of FIG. 9 shows anenlarged view of the back surface.

In the second embodiment, the black matrix BM is formed oflow-resistance conductors that are arranged to extend in parallel atpredetermined pitches, and low-resistance conductors that areelectrically connected to and cross the conductors and extend inparallel at other predetermined pitches. The black matrix BM is providedwith cutoff parts to form a plurality of electrodes that extend in apredetermined direction (the vertical direction in FIG. 9). The width ofeach cutoff part is shorter than an interval (a pitch) between theadjacent low-resistance conductors extending in the predetermineddirection. The cutoff parts are provided at intervals of a plurality ofpitches in the horizontal direction. Thus, the influence of lightleakage from the cutoff parts on the display image is small enough notto cause any problem.

The first touch electrodes 3 a can be formed by drawing a plurality ofelectrodes formed by processing the black matrix BM as described aboveto be brought into contact with the connecting part 21. Although eachcutoff part is provided on a vertical straight line in the upper rightpart of FIG. 9, the cutoff part is not limited to this form, but may beprovided to form a plurality of electrodes that extend in a desireddirection.

The second touch electrodes 3 b may be formed in the same form as thatof the first embodiment, or may be formed of low-resistance conductorsin the same manner as the first touch electrodes 3 a of the secondembodiment. Forming both the touch electrodes 3 a and 3 b oflow-resistance conductors suppresses attenuation of the touch signal.

According to the second embodiment, it is possible to further reduce thethickness and the weight of the display device.

Variation of the Second Embodiment

In a variation of the second embodiment, first touch electrodes 3 a arelaminated on a black matrix BM of an optical substrate 9.

FIG. 10 is a diagram illustrating a structure of touch electrodes in thedisplay device according to the variation of the second embodiment.

The lower part of FIG. 10 shows a cross-sectional view of the displaydevice of the variation. Because the cross-sectional view is the same asthe cross-sectional view of the display device shown in the lower partof FIG. 8, detailed explanation thereof is omitted. The upper left partof FIG. 10 shows a plan view of the back surface of the opticalsubstrate 9 as viewed from inside. The upper right part of FIG. 10 showsan enlarged view of the back surface.

In the variation, low-resistance conductors are formed and laminated onthe black matrix BM. Because the conductors are laminated on the blackmatrix BM, the conductors are not required to be light-transmittingmaterial, such as ITO indicated in the first embodiment. Thus, it ispossible to use a material having low electric resistance even if it isa non-light-transmitting material.

The conductors are provided with cutoff parts to form a plurality ofelectrodes that extend in a predetermined direction (the verticaldirection in FIG. 10). The width of each cutoff part is shorter than aninterval (a pitch) between the adjacent low-resistance conductorsextending in the predetermined direction.

The electrodes formed as described above are drawn to the frame side andbrought into contact with a connecting part 21, and thereby theelectrodes can be functioned as first touch electrodes 3 a. Althougheach cutoff part is provided on a vertical straight line in the upperright part of FIG. 10, the cutoff part is not limited to this form, butmay be provided to form a plurality of electrodes that extend in adesired direction.

Second touch electrodes 3 b may be formed in the same form as that ofthe first embodiment, or may be formed of low-resistance conductors inthe same manner as the first touch electrodes 3 a of the secondembodiment. Forming both the touch electrodes 3 a and 3 b oflow-resistance conductors suppresses attenuation of the touch signal,and produces a touch signal with high sensitivity.

According to the variation of the second embodiment, it is possible toobtain a touch sensor electrode with high sensitivity.

Comparison With Other Structures

The embodiments explained above have the structure provided with thetouch electrodes 3 a and 3 b without the touch panel substrateillustrated in FIG. 1. However, various forms exist as the structureprovided with the touch electrodes 3 a and 3 b without a touch panelsubstrate. The following is explanation of advantages of the presentapplication as compared with these various structures.

FIG. 11 is a cross-sectional view illustrating a structure of a displaydevice discussed to be compared with the display device of the presentembodiment. In the display device illustrated in FIG. 11, touchelectrodes 3 a and 3 b are provided on the front surface of the opticalsubstrate 9.

In the structure illustrated in FIG. 11, the touch electrodes 3 a and 3b are formed after forming an array substrate 4, an OLED light-emittingdisplay layer 5, a moisture impermeable film 6, a filler 8, and anoptical substrate 9 in a laminated manner. In the formation, because twoelectrode layers are provided, the manufacturing process is morecomplicated than the case of providing one electrode layer. For example,although one electrode layer can be simply formed by mask deposition,providing two electrode layers requires repeatedly executing processing(metal patterning, etching, and interlayer film formation) with a photomask. However, the processing steps are executed after formation of theOLED light-emitting display layer 5 that must be protected frominfiltration of moisture, and protection from water is indispensable.Thus, forming the touch electrodes of two layers on the surface of theoptical substrate 9 greatly complicates the manufacturing process.

FIG. 12 is a cross-sectional view illustrating a structure of a displaydevice discussed to be compared with the display device according to thepresent embodiment. In the display device illustrated in FIG. 12, thetouch electrodes 3 a and 3 b are provided on the front surface and theback surface of the optical substrate 9, respectively.

In the structure illustrated in FIG. 12, an optical substrate 9 having aback surface provided with the touch electrodes 3 b in advance is bondedto the filler 8, and thereafter touch electrodes 3 a of a single layercan be formed on the front surface of the optical substrate 9. Thus,this structure simplifies the manufacturing process in comparison withthe structure of FIG. 11. However, this structure requires increase ofthe step of attaching an FPC to extract a signal from the touchelectrodes 3 b formed on the back surface, and increase in size of theoptical substrate 9. Thus, this structure has demerits in both the costand the module size.

FIG. 13 is a cross-sectional view illustrating a structure of a displaydevice discussed to be compared with the display device according to thepresent embodiment. In the display device illustrated in FIG. 13, thetouch electrodes 3 a and 3 b are provided on the front surface and theback surface of the optical substrate 9, respectively. In addition, asignal of the touch electrodes 3 a on the back surface is extracted ontothe array substrate 4 via the seal material 7 and the moistureimpermeable film 6.

However, in the structure illustrated in FIG. 13, it is difficult toextract a signal of the touch electrodes 3 a onto the array substrate 4.Specifically, in the case where a signal is extracted via the sealmaterial 7, the signal can be extracted using conductive particulatessuch as Au-plated pearl spacers. However, it is impossible to useconductive particulates for the moisture impermeable film 6, and it isalso difficult to process the moisture impermeable film 6. Thus, it isimpossible to construct any process that can be put into practice.

However, the structure illustrated in FIG. 13 can be constructed with apractical process, when it becomes possible to process the moistureimpermeable film 6, or when it is possible to receive and transmitsignals by, for example, capacity coupling, without processing themoisture impermeable film 6. Thus, the structure illustrated in FIG. 13is not excluded from the present application, but claimed as the thirdembodiment.

While certain embodiments have been described, these embodiments havebeen presented by way of example only, and are not intended to limit thescope of the inventions. Indeed, the novel embodiments described hereinmay be embodied in a variety of other forms; furthermore, variousomissions, substitutions and changes in the form of the embodimentsdescribed herein may be made without departing from the spirit of theinventions. The accompanying claims and their equivalents are intendedto cover such forms or modifications as would fall within the scope andspirit of the inventions.

For example, although the external extraction electrode 20 is connectedwith the first touch electrodes 3 a via conductive particulates in theabove embodiments, signals may be transmitted and received between theelectrodes via capacitive elements (parasitic capacitance) formedbetween the electrodes, when the interval between the electrodes can beshortened and the areas of the electrodes can be increased. Signals mayalso be transmitted and received between the external extractionelectrode 20 and the second touch electrodes 3 b via capacitive elements(parasitic capacitance).

Various inventions can be made by proper combinations of a plurality ofconstituent elements disclosed in the above embodiments. For example,some constituent elements may be deleted from the constituent elementsdisclosed in the embodiment. In addition, constituent elements ofdifferent embodiments may be used in combination.

What is claimed is:
 1. A display device comprising: a first substrateincluding a first region and a second region surrounding the firstregion; a sealing film covering the first region and the second region;and a touch sensor above the sealing film, wherein the first regionincludes organic light emitting elements arranged in a matrix, the touchsensor includes touch electrodes, each of the touch electrodes extendsin a first direction, the touch electrodes are arranged in a seconddirection differing from the first direction, each of the touchelectrodes includes protruded portions, and each of the protrudedportions extends in a predetermined direction.
 2. The display deviceaccording to claim 1, wherein one of the touch electrodes is adjacent toanother of the touch electrodes, and each of the protruded portions ofthe one of the touch electrodes faces a corresponding one of theprotruded portions of the another of the touch electrodes in thepredetermined direction.
 3. The display device according to claim 2,wherein one of the protruded portions of the one of the touch electrodesfaces one of the protruded portions of the another of the touchelectrodes with a gap in the predetermined direction, each of the touchelectrode includes openings in a matrix, and the gap is smaller than awidth of one of the openings in the predetermined direction.
 4. Thedisplay device according to claim 1, further comprising: electrodeswhich are connected to a drive circuit configured to drive the organiclight emitting elements and are arranged between the sealing film andthe first substrate; and a resin layer which covers the sealing film andoverlaps the first region in a plan view, wherein the electrodes overlapthe second region of the first substrate, each of the touch electrodesincludes a first portion overlapping the first region and a secondportion overlapping the second region, the first portion includes theprotruded portions, the second portion is arranged between the sealingfilm and the resin layer, the second portion includes a side surfacecovered by the resin layer, a bottom surface covered by the sealingfilm, and an upper surface covered by the resin layer, and each of theelectrodes is arranged between the sealing film and the first substrate.5. The display device according to claim 1, further comprising:electrodes which are connected to a drive circuit configured to drivethe organic light emitting elements and are arranged between the sealingfilm and the first substrate; and a resin layer which covers the sealingfilm and overlaps the first region in a plan view, wherein theelectrodes overlap the second region of the first substrate, each of thetouch electrodes includes a first portion overlapping the first regionand a second portion overlapping the second region, the first portionincludes the protruded portions, the second portion is arranged betweenthe resin layer and the first substrate, each of the electrodes isarranged between the sealing film and the first substrate, and a firstFPC terminal connected to each of the electrodes and a second FPCterminal connected to the second portion are arranged on a third regionof the first substrate arranged outside a region of the first substratecovered by the sealing film.
 6. A display device comprising: a firstsubstrate including a first region and a second region surrounding thefirst region; a sealing film covering the first region and the secondregion; and a touch sensor above the sealing film, wherein the firstregion includes organic light emitting elements arranged in a matrix,the touch sensor includes touch electrodes, each of the touch electrodesextends in a first direction, the touch electrodes are arranged in asecond direction differing from the first direction, each of the touchelectrodes includes pairs of protruded portions, the pairs of protrudedportions are arranged at regular intervals in each of the touchelectrodes, and each of the pairs of protruded portions extends in apredetermined direction.
 7. The display device according to claim 6,wherein one of the touch electrodes is adjacent to another of the touchelectrodes, and each of the pairs of protruded portions of the one ofthe touch electrodes faces a corresponding pair of the pairs ofprotruded portions of the another of the touch electrodes in thepredetermined direction.
 8. The display device according to claim 7,wherein each of the pairs of the protruded portions of the one of thetouch electrodes faces a corresponding pair of the pairs of theprotruded portions of the another of the touch electrodes with a pair ofgaps in the predetermined direction, each of the touch electrodeincludes openings in a matrix, and each of the gaps is smaller than awidth of one of the openings in the predetermined direction.
 9. Thedisplay device according to claim 6, further comprising: electrodeswhich are connected to a drive circuit configured to drive the organiclight emitting elements and are arranged between the sealing film andthe first substrate; and a resin layer which covers the sealing film andoverlaps the first region in a plan view, wherein the electrodes overlapthe second region of the first substrate, each of the touch electrodesincludes a first portion overlapping the first region and a secondportion overlapping the second region, the first portion includes theprotruded portions, the second portion is arranged between the sealingfilm and the resin layer, the second portion includes a side surfacecovered by the resin layer, a bottom surface covered by the sealingfilm, and an upper surface covered by the resin layer, and each of theelectrodes is arranged between the sealing film and the first substrate.10. The display device according to claim 6, further comprising:electrodes which are connected to a drive circuit configured to drivethe organic light emitting elements and are arranged between the sealingfilm and the first substrate; and a resin layer which covers the sealingfilm and overlaps the first region in a plan view, wherein theelectrodes overlap the second region of the first substrate, each of thetouch electrodes includes a first portion overlapping the first regionand a second portion overlapping the second region, the first portionincludes the protruded portions, the second portion is arranged betweenthe resin layer and the first substrate, each of the electrodes isarranged between the sealing film and the first substrate, and a firstFPC terminal connected to each of the electrodes and a second FPCterminal connected to the second portion are arranged on a third regionof the first substrate arranged outside a region of the first substratecovered by the sealing film.